9. (10 points) Given f (x) = x4 + 6x3 + 9x2 + 6x + 8 and that x = -2 is a zero, find the other real and complex zeros. Must show your work. 10. (8 points) An engineer collects data showing the speed "'s" of a given car model and its average miles per gallon "M". Speed, s mpg, M 20 18 30 20 140 23 150 125 60 28 70 124 80 22 a.) Use a graphing calculator to plot the scatter diagram. Copy a sketch of the graph below. b.) What is the quadratic function of best fit? Make sure to write the function in terms of correct input and output symbols given in the problem. Round values to the nearest thousandth. c.) Find the miles per gallon when the speed is 75 miles per hour. Round to nearest mile. d.) At what speed does the miles per gallon reach the maximum value